"The government is due to revamp the line-up to pursue its diplomacy in the Asia-Pacific region," public broadcaster NHK reported Tuesday, citing the planned replacement of Japan's Ambassador to China, Uichiro Niwa.

Japanese media has also reported in the past few days the planned replacements of ambassadors in Seoul and Washington.

The government is expected to officially announce the moves after the current session of parliament ends on September 8, Kyodo news agency has reported.

The foreign ministry declined to comment on the reports.

Tokyo's territorial row with Beijing flared up anew as activists from Hong Kong landed on Japan-administered islands in the East China sea claimed by China. They were followed days later by Japanese nationalists.

Separately, South Korean President Lee Myung-Bak visited islets in the Sea of Japan (East Sea) controlled by his country but claimed by Japan, sending relations plunging.

Tokyo's ties with Washington have also stalled over the relocation of a major US military base on the Japanese island of Okinawa.

Niwa sparked controversy in June when he expressed objections to the Tokyo municipal government's plan to buy disputed islands, saying the move could spark an "extremely grave crisis" between the Asian powers.

"We have started to raise funds to build a temple for Mazu on the Diaoyu islands, so the goddess can protect the safety of our fishermen and bless their work," said activist Tony Huang.

Huang declined to say how much money has been raised so far but added that a key religious ritual needed to set up the temple has already been completed.

The ceremony consists of moving a statue of the goddess out of an existing temple in preparation for transporting it to its planned new home on the Diaoyu islands, Huang said.

Taiwanese activists are also planning to sail to the disputed islands again, even though they were forced to abort a plan last week after failing to hire a ship, he said.

The islands, known as Diaoyu in Chinese and Senkaku in Japanese, are claimed by Taiwan, as well as by China and Japan. They are administered by Tokyo.

They have sparked a major row between China and Japan after activists from both sides sailed to the archipelago in the past week.

Japan arrested 14 activists who sailed to the island from Hong Kong, triggering protests by China and Taiwan, and moved swiftly to deport them.

Meanwhile, Japanese activists landed on one of the islands and raised a Japanese flag, just days after Tokyo deported the pro-China protesters.

Taiwan has joined the row, summoning Japan's representative on Sunday to protest the trip by the country's activists.

The islands may lie on top of significant oil reserves, and their strategic value is considerable, but according to observers national pride is also a major reason for the acrimony in the dispute.